Ported X head pics

Your X head probably flows a little better stock than a factory stock 71 2.02 J head. X’s are right about 200cfm with valves that are not sunk, they have a better short turn also, I think with just a gasket match, a little slimming of the guide and removing the guide tail that curves, good 11/32 stem valves / and valve job, minor bowl blending you would be at 225cfm enough for 450 HP.